An important semiconductor manufacturing process, such as a lithography (exposure) process, must be performed in a clean room where lithography machines are located. Typically, such a semiconductor manufacturing process is performed under a certain air condition. Namely, airborne molecular contamination (AMC) in the clean room must be precisely controlled, such that the semiconductor manufacturing process can be successfully performed. Airborne molecular contamination can include total organic compound (TOC), NH3, and total sulfur (TS), for example.
A conventional clean room includes multiple floors and a plurality of machines for manufacturing semiconductors are disposed therein. A conventional air supply system is deployed in the clean room to provide clean air for the clean room. The conventional air system utilizes a make-up air unit (MAU) to remove the airborne molecular contamination (AMC) of the outdoor air. A conventional make-up air unit includes an air washer to wash the outdoor air with spraying water. However, the water spray based air washer needs a large amount of water for scrubbing the outdoor air and lots of electricity for pumping the water.
The conventional make-up air unit needs a water eliminator to prevent an air flow with water droplets to the downstream of the MAU. The water eliminator may cause a pressure drop of the airflow and a higher pressure drop may cause a higher MAU fan power consumption.